About the Light Year Converter
A light year is the distance light travels in one Julian year: about 9.46 trillion kilometres. It is a distance, not a time, and it is the natural yardstick for anything outside the solar system. Enter a value in any unit below and this converter gives the equivalent in all the others.
Also known as: light years to km, light year to miles, ly converter, how far is a light year, light year in km.
How to use this calculator
- Enter value, unit.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
1 light year = 9.4607 × 10¹² km = 63,241 AU = 0.3066 pc
Worked example
Using the values pre-filled in the calculator above:
- Value = 1
- Unit: Light years
the calculator returns:
- Light years: 1
- Kilometres: 9,460,730,472,580.8
- Miles: 5,878,625,373,183.607
- Astronomical units: 63,241.077084